Rotate markers in Scatter plot #2478

mgoacolou · 2013-09-30T14:18:52Z

This a re-summit of the #2432

Make possible to give a scalar or an array for rotate markers. This is usefull for representing for example Speed, Type, Direction of mobile targets.

mdboom · 2013-09-30T14:56:44Z

lib/matplotlib/collections.py

+            if self._sizes.size > self._angles.size:
+                self._angles = np.ma.resize(self._angles, self._sizes.shape)
+            else:
+                self._sizes = np.ma.resize(self._sizes, self._angles.shape)


This is different from the behavior of other collection parameters that "wrap around" -- that is, for a given symbol N, the angle would be angles[N % len(angles)].

this is what exactly do np.ma.resize

I don't think it's the same. Here's the current behavior. Say you have 3 sizes (A, B, C) and 2 colors (X, Y), then you get the following combinations:

(A, X)
(B, Y)
(C, X)

I think with the above, you would only get the minimum number of either the sizes or angles.

That said, I think to get this behavior, and be consistent with the other properties, you'll have to extend the backends to understand angles.

tacaswell · 2014-01-05T22:41:57Z

lib/matplotlib/axes/_axes.py

@@ -3138,7 +3138,7 @@ def dopatch(xs, ys):
                    medians=medians, fliers=fliers)

    @docstring.dedent_interpd
-    def scatter(self, x, y, s=20, c='b', marker='o', cmap=None, norm=None,
+    def scatter(self, x, y, s=20, c='b', marker='o', angles=0, cmap=None, norm=None,


The new kwarg should be at the end to preserve reverse compatibility.

tacaswell · 2014-01-05T22:44:29Z

You should not merge master into your working branch, but re-base your branch onto current master. Please remove the merge commit and rebase your commit.

tacaswell · 2014-01-30T01:45:15Z

This needs another rebase and to have a few remaining comments addressed.

tacaswell · 2014-02-25T04:16:17Z

@mgoacolou I have re-milestoned this as 1.5.x as this needs a re-base and we have not heard from you in a few months. If you can get this re-based and fixed up in the near future we can get it in to 1.4.0.

mgoacolou · 2014-02-25T11:17:19Z

I'm testing my rebase

tacaswell · 2014-02-25T18:37:00Z

lib/matplotlib/axes/_axes.py

@@ -3469,6 +3472,7 @@ def scatter(self, x, y, s=20, c='b', marker='o', cmap=None, norm=None,
            raise ValueError("x and y must be the same size")

        s = np.ma.ravel(s)  # This doesn't have to match x, y in size.
+        angles = np.ma.ravel(angles)  # This doesn't have to match x, y in size.


This is one character too long for pep8.

tacaswell · 2014-02-25T18:37:47Z

one of the image tests seems to be consistently failing

======================================================================

FAIL: matplotlib.tests.test_transforms.test_pre_transform_plotting.test

----------------------------------------------------------------------

Traceback (most recent call last):

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/nose/case.py", line 197, in runTest

self.test(*self.arg)

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/matplotlib-1.4.x-py2.7-linux-x86_64.egg/matplotlib/testing/decorators.py", line 50, in failer

result = f(*args, **kwargs)

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/matplotlib-1.4.x-py2.7-linux-x86_64.egg/matplotlib/testing/decorators.py", line 201, in do_test

'(RMS %(rms).3f)'%err)

ImageComparisonFailure: images not close: /home/travis/build/matplotlib/tmp_test_dir/result_images/test_transforms/pre_transform_data.png vs. /home/travis/build/matplotlib/tmp_test_dir/result_images/test_transforms/pre_transform_data-expected.png (RMS 20.345)

mgoacolou · 2014-02-26T09:17:45Z

I corrected the bug in computation of scale. The figure (expected and generated) are close but have not the same x/y limites. Is there a way to know why?

tacaswell · 2014-02-26T17:10:54Z

lib/matplotlib/collections.py

@@ -709,32 +709,121 @@ class _CollectionWithSizes(Collection):
    """
    Base class for collections that have an array of sizes.
    """
+    def __init__(self):


This is a major change as sub-class are not guaranteed to call Collections.__init__ because it used to be a no-op (the default) function.

super() guarantees the call of all init and only once if they exists

tacaswell · 2016-03-22T01:53:38Z

@mgoacolou any interest in continuing to work on this?

RegularPolyCollection already has a rotation param. Probably should be consistent with that naming.

mgoacolou · 2016-03-22T21:12:13Z

@tacaswell Hi, I am now more confident with git now. I'll take a look this week on this.

apply incrementaly the Affine2D transform for size and angle use super for draw method

…ameters

flying-sheep · 2016-03-23T13:28:32Z

oh nice, definitely looking forward to this?

so am i correct that after this is in, i can e.g. do:

df = pd.DataFrame({X: ..., Y: ..., C: ['Foo', 'Bar', ...]})
marker_map = {'Foo': 'o', 'Bar': 'x'}

plot(df.X, df.Y, marker=[marker_map[c] for c in df.C])

tacaswell · 2016-03-23T13:38:56Z

No, this is the other meaning of rotate as in 'change the orientation of the marker'. Basically quiver, but with any marker not just arrows.

There are deep performance related issue that plot has exactly one marker. I would do what you want as

for k, _df in df.group_by('C'):
    ax.plot(_df,X, _df.Y, **style_map[k])

flying-sheep · 2016-03-23T14:10:01Z

is there a more ggplot-like interface to matplotlib? i.e. where you give a DataFrame and column names to x, y, marker, c, and so on and it does _the right thing_™ (including legends)?

seaborn just has its own high-level plots, and pandas’ DataFrame.plot only allows specifying x and y in this way.

i basically want to do: scatter('Height', 'Weight', c='Age', marker='Gender'), and it uses the color cycle for categorical variables and the colormap for continuous ones, plots legend(s) and colorbar(s) and presto!

WeatherGod · 2016-03-23T14:16:21Z

We are working towards supporting a more robust API like that. You can get
partly there right now by passing the dataframe as the "data" argument and
use the string names for the x and y arguments. I don't think we support
the color and marker arguments yet, though.

On Wed, Mar 23, 2016 at 10:10 AM, Philipp A. notifications@github.com
wrote:

is there a more ggplot-like interface to matplotlib? i.e. where you give a
DataFram and column names to x, y, marker, c, and so on and it does _the
right thing_™ (including legends)?

seaborn just has its own high-level plots, and pandas’ DataFrame.plot only
allows specifying x and y in this way.

i basically want to do: scatter('Height', 'Weight', c='Age',
marker='Gender'), and it uses the color cycle for categorical variables
and the colormap for continuous ones.

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#2478 (comment)

flying-sheep · 2016-03-23T14:32:17Z

currently, mpl works on a “series-based” level, which imho makes no sense for multidimensional data: you can have one dimension represented by shape, the other by color, the third by size, and two more by x/y position. this results in an exponential number of series.

therefore to make sense, your API must deviate from the previous model, and simply track 1. each point individually and 2. each represented feature via legend (marker shape, discrete color), colorbar (continuous color), “volume slider triangle” or axis label (x/y position).

like this, but using an isosceles trapezoid as “colorbar for size”:

tacaswell · 2016-03-23T15:21:52Z

color and size should work with scatter + data, but not marker.

The pandas/table/dataframe/R view of data is not universal or fundamental where as vectors / arrays of number are, hence that is what the core of mpl targets and will continue to target.

There is definitely interest from many parties for there to a pandas-aware domain-specific plotting library that lives under the matplotlib gh umbrella organization that can require pandas and do these 'magic' things. The only hold up is developer time. @flying-sheep You have any interest in leading this effort?

That said, scatter creates a PathCollection and it should be pretty easy to extend it to take a vector of shapes instead of broadcasting a single shape.

flying-sheep · 2016-03-23T15:43:41Z

i don’t know if i’m suited, but i’d definitely like to chime in wherever discussion is happening regarding the data= API. (where does it happen? could you give me a link?)

regarding an universal interface, i disagree: the grammar of graphics is a deconstruction/analysis of the way data visualization happens. and those rules do directly translate into a data frame structure: a heterogeneous collection of feature columns that each carry one entry for each sample.

by mapping those feature columns onto graphical features, we get all possible permutations of visualizations. so basically, we have to (implicitly or explicitly) reshape our data into this structure anyway when visualizing it, so we might as well use an interface optimized for this shape (pandas.DataFrame)

tacaswell · 2016-03-23T15:48:02Z

The data kwarg API shipped with v1.5.0.

flying-sheep · 2016-03-23T16:27:54Z

ah, OK, so this ship has sailed then. damn.

i submitted #6214 for further discussion

WeatherGod · 2016-03-23T16:35:33Z

I am not sure what you mean by "this ship has sailed". All we implemented
was a generic way to access data within a dataframe or other similar
objects, and a minimal usage. I don't see any limitations to extending the
syntax, but that'll have to be done judiciously, like how this first round
of the API was done. There are a few technical improvements that will be
needed (having multiple norms, be able to modify more properties, etc), but
we have been wanting to implement them for awhile now.

On Wed, Mar 23, 2016 at 12:27 PM, Philipp A. notifications@github.com
wrote:

ah, OK, so this ship has sailed then. damn.

i submitted #6214 #6214
for further discussion

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#2478 (comment)

jklymak · 2018-10-05T23:16:17Z

... I'm going to close this as abandoned. I'm also not aware that anyone has asked for this functionality for quite a while, and while it looks cool its a significant complication to the code... Feel free to re-open or ask to have it re-opened if I'm closing in error.

mdboom reviewed Sep 30, 2013
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tacaswell mentioned this pull request Jan 5, 2014

Rotate markers in Scatter plot #2432

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tacaswell reviewed Jan 5, 2014
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tacaswell modified the milestones: v1.5.x, v1.4.0 Feb 25, 2014

tacaswell modified the milestones: v1.4.0, v1.5.x Feb 25, 2014

tacaswell reviewed Feb 25, 2014
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tacaswell reviewed Feb 26, 2014
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tacaswell added the needs_revision label Mar 8, 2014

tacaswell modified the milestones: v1.5.x, v1.4.0 Apr 4, 2014

tacaswell modified the milestones: proposed next point release, next point release Feb 19, 2015

tacaswell modified the milestones: proposed next point release, next point release Jun 22, 2015

mgoacolou added 3 commits March 22, 2016 23:12

Rotate markers in Scatter plot

fdf0a68

Rename _CollectionWithRotations to _CollectionWithAngles

ead934d

apply incrementaly the Affine2D transform for size and angle use super for draw method

apply only once the scale and rotation

f2107c2

mgoacolou added 4 commits March 22, 2016 23:17

correct the angle orientation to clock-wize

dec2f18

unset affine transform for size and angle before applying the new par…

5871024

…ameters

resize transforms to feat at least the sizes/angles length

c8574a2

correct the kw passing to Collection from PathCollection

57ac137

mgoacolou force-pushed the master branch from c7ded09 to 57ac137 Compare March 22, 2016 22:37

tacaswell modified the milestones: 2.2 (next next feature release), 2.1 (next point release) Aug 13, 2017

jklymak closed this Oct 5, 2018

Polirecyliente mentioned this pull request Dec 29, 2020

Rotate Markers in functions like plot, scatter, etcetera #19195

Closed

story645 removed this from the future releases milestone Oct 6, 2022

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Rotate markers in Scatter plot #2478

Rotate markers in Scatter plot #2478

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